Factoring database - Page 93

rekcahx · 2011-01-16, 13:34

I found a problem from the DB.

http://factordb.com/index.php?id=1100000000217043267

This 7 digit number 1210012 is fully factored, but its status is still "C".

lorgix · 2011-01-16, 13:36

It's the '%' again. It has been discussed earlier in the thread.

henryzz · 2011-01-16, 13:38

Quote:

Originally Posted by lorgix

It's the '%' again. It has been discussed earlier in the thread.

Yes http://factordb.com/index.php?query=1210012 is correct.

wblipp · 2011-01-16, 20:22

Is there a way to get the database's known factorizations of the form p^q-1, p an odd prime, q a prime?

rekcahx · 2011-01-16, 20:53

Quote:

Originally Posted by wblipp

Is there a way to get the database's known factorizations of the form p^q-1, p an odd prime, q a prime?

Maybe.
In example: http://factordb.com/index.php?query=x^3-1&use=x&x=2&VP=on&OD=on&PR=on&FF=on&PRP=on&CF=on&U=on&C=on&perpage=200&format=1&sent=Show

kar_bon · 2011-01-17, 09:56

Quote:

Originally Posted by wblipp

Is there a way to get the database's known factorizations of the form p^q-1, p an odd prime, q a prime?

In the factorDB see the link Factor tables and from the listed tables choose Others.

There're several terms listed, including Cunningham numbers b^n-1.

Choose 'Show' to get the screen of this table.
Deselect "b is even" and "b is composite", n is set to 1 by default (fill in a different value if needed) and click 'Show' to update the results.

Andi47 · 2011-01-17, 18:48

Sequence 84822 is broken, see here: http://www.mersenneforum.org/showthread.php?t=14859

wblipp · 2011-01-17, 20:53

Quote:

Originally Posted by kar_bon

In the factorDB see the link Factor tables and from the listed tables choose Others.

There're several terms listed, including Cunningham numbers b^n-1.

Choose 'Show' to get the screen of this table.
Deselect "b is even" and "b is composite", n is set to 1 by default (fill in a different value if needed) and click 'Show' to update the results.

It looks like if a page would require numbers that have not been previously considered, they are automatically generated and trial factored - is that right?

warut · 2011-01-17, 22:08

I've noticed that the database erroneously omits some small factors of the following 77-digit numbers:

Code:

 
80978084394598568390520920252440060895670346459831516622284554518849503146397
82609404176288347510975214065063503631619108607371480044587508148396968704911
88236918639719858997946921372584311423090252002347982879826766163694271697843
88894857952232839709785628818457172955757575436001096904562755715875193607509
92250106588933435730861605431146390431716761868772836262451636991161111409211
96219970786531934764768710647149833037379504561939264511368166182316972958369

warut · 2011-01-17, 23:42

Quote:

Originally Posted by wblipp

It looks like if a page would require numbers that have not been previously considered, they are automatically generated and trial factored - is that right?

Yes.

mdettweiler · 2011-01-18, 06:17

@Syd: just curious, what program are you using for N-1 and N+1 tests? I tried putting in a known small-ish prime with a trivial N+1 factorization (50633872*3^25032-1) to have the DB take a whack at it, and it somewhere in the vicinity of 12-20 minutes to do the N+1 test. My computer took just 90 seconds to do it even with the old (1.2) version of PFGW, so I'm guessing you must be using something different.

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2011-01-16, 13:34	#1013
rekcahx Oct 2009 Oulu, Finland 2×3×5 Posts	I found a problem from the DB. http://factordb.com/index.php?id=1100000000217043267 This 7 digit number 1210012 is fully factored, but its status is still "C".

2011-01-16, 13:36	#1014
lorgix Sep 2010 Scandinavia 3·5·41 Posts	It's the '%' again. It has been discussed earlier in the thread.

2011-01-16, 20:22	#1016
wblipp "William" May 2003 New Haven 2·7·13² Posts	Is there a way to get the database's known factorizations of the form p^q-1, p an odd prime, q a prime?

2011-01-17, 18:48	#1019
Andi47 Oct 2004 Austria 2·17·73 Posts	Sequence 84822 is broken, see here: http://www.mersenneforum.org/showthread.php?t=14859

2011-01-18, 06:17	#1023
mdettweiler A Sunny Moo Aug 2007 USA (GMT-5) 3×2,083 Posts	@Syd: just curious, what program are you using for N-1 and N+1 tests? I tried putting in a known small-ish prime with a trivial N+1 factorization (50633872*3^25032-1) to have the DB take a whack at it, and it somewhere in the vicinity of 12-20 minutes to do the N+1 test. My computer took just 90 seconds to do it even with the old (1.2) version of PFGW, so I'm guessing you must be using something different.